Arboretum cam nest....

For those not reading the Facebook page, the Arboretum cam nest laid it’s first egg on May 3-4, the second egg on May 7 and the third egg on May 10. Like clockwork, every third day! They gave us a scare when the male brought a large sheet of plastic to the nest and the female struggled with it....at one point it was completely covering her. Viewers were concerned that the adults would die, but they are always free to fly away and were in no danger. The concern was for the eggs. I watched another nest many years ago where the male brought some landscape fabric to the nest and when it covered the eggs, and they could no longer see them, they quit incubating and the eggs died, the nest failed. But in this case, although it was very frustrating to observe, the plastic got moved to the nest edge and finally blew away. Whew!
Ospreys are known for bringing interesting things to their nests. Over the years we found many funny things in the nests during banding, a lanyard with keys attached, hats, gloves, an arrow, etc. They  are also known for bringing dangerous things to the nest, like baling twine. We have rescued too many chicks that became tangled up in it. Last year I found a chick hanging dead from the nest edge tangled in orange baling twine. It wasnt the first time either.
Here is the link to the cam... http://www.arboretum.umn.edu/ospreycam.aspx

May 20.....

It’s been a crazy few weeks but I will try to share some interesting stories with you about our Ospreys. First of all, I know that many of you are curious about our single dad from last year. He did find a  beautiful mate. I visited the nest many times and without exception, every time he tried to copulate with her, she was unreceptive (would not lift her tail) and the attempt was unsuccessful. I was beginning to think that perhaps she was too young to breed. It was discouraging to think that a whole breeding season might be wasted for him. But he and his new mate are now incubating eggs! Of course the amount of time I was at the nest may have only been several hours in a week, so there surely were many copulation attempts when I was not there. I do wonder if the eggs will be fertile, but once again I am keeping my fingers crossed for this fellow. 

 Me and my team are still working hard on getting the bands read, tho every year there are fewer banded birds, which is rapidly destroying the behavioral research. We still are hoping to find a master bander who wants to get involved and help us remedy this situation. We have documented a lot of movements between nests among the banded birds and I am still sorting out final territories! Most Ospreys have laid eggs now, which makes the band reading more difficult and can take many  hours as we wait for the birds to switch places. And often when they do take their shift on the eggs, the exchange can happen so quickly that all we can determine is IF a bird is banded or not. Females tend to stay closer to the nest during their break time, but the males often disappear. We are learning patience and perseverance! Because the birds do move around a lot in the early part of the breeding season we have to read and re read bands. Usually by the time eggs are laid, the game of musical nests has settled down. Most incubation dates are several weeks later than in past years so it will be interesting to see how this impacts overall productivity. Will we see more Ospreys remaining here until late September or October this year? Will we see fewer chicks on productive nests or more failed nests? We are finding new nests, and have at least six  so far that were not included in last years count. I am very sad to report that two of our oldest males did not return this year. They were 23 and 18 last year. They have been replaced by unbanded birds. I have known both of those birds for so long.....there have been a lot of goodbyes in recent years, the result of doing this research for 25 years. 

A threesome?

Life remains pretty darn interesting in the Osprey world! I am still documenting a lot of musical nests....birds moving around, some still waiting for a mate, or looking for a mate. I am finding nests that have been unused for several years are suddenly reoccupied, have found several new nests already this year as well. Today I found a nest with two females and a male on it! The females were coexisting peacefully, one had a fish, the other was just waiting calmly as the male ate a fish nearby. I did not see any copulation, which might have given me some clues about what is actually occurring. Is there just an extra female being tolerated temporarily by a bonded pair....or is it really a threesome, with both females getting food and copulating with the male? Hmmmmm. I visited a lot of nests and covered 120+ miles, read some bands and found a lot of unbanded birds. Yesterday I revisited the single dad and found him still hanging around with the new female. I have not seen them copulate successfully yet but I am hopeful tho!
There are still so many bands to read and the light is just not cooperating. I really need some cool cloudy days to help me get the bands documented. I am finding more and more nests that have laid eggs. There are so many nests that I have not even gotten to once this year....my time has been so limited lately. I know we have a lot of new readers who may be looking for basic information so do feel free to ask questions! The books say that Ospreys incubate between 35-43 days and many years ago, when I had only a few nests to watch, I determined that they most often hatch on day 39. Researchers in Pennsylvania also arrived at the same number. Of course there can be some variation, especially if the first egg does not hatch. I see that osprey researchers in other places have come up with a slightly different number. During this phase, both male and female will incubate so we watch for the changing of the guard. Usually when the male brings a fish, the female will take it and leave to eat her fish nearby. The male will then take over the incubation duties. In fact one of the tell tale signs that hatching has begun is that the female will NOT leave with the fish, but will begin taking small bites and leaning into the nest cup to feed the wee ones that can’t be seen at first. So this is a behavior to pay attention to....the alternating of incubators, so that when this behaviors changes, we can recognize the early signs of hatching.